This invention relates to harvester headers and more particularly to the construction of frames for such headers. The invention has particular utility for a forage harvester header but it may also have application to other agricultural equipment such as combine headers.
Forage harvester headers are used to cut and convey standing row crops from a standing position in the field to the harvester for processing. Heretofore, frames for such headers were made by welding together a plurality of subframes into a weldment of the general configuration of the header. It is also conventional to add strength and rigidity to the weldment by the provision of a transverse beam welded to the bottom rear of the header. The functional components were mechanically attached by bolting or welding directly to the weldment or main frame.
The use of a weldment as a main frame for a header has given rise to a number of problems. First, it is difficult to align accurately the subframe for welding often resulting in the manufacture of misaligned or dimensionally inaccurate frames. Secondly, the welding operation, by the application of heat, inherently causes distortion of the parts. A misaligned or inaccurate frame can lead to inoperability or poor functioning of the functional components which are attached to the frame. Sometimes, the misalignment of frames can be corrected by rewelding or by machining some of the frame surfaces to tolerance. Even when these solutions are practical, they are costly.